1. Field of the Invention
The invention relates to a heating device, particularly an automotive heating device which can be operated with liquid or gaseous fuel. Conventionally, such a heating device has a burner, and a combustion chamber that is defined by a combustion pipe.
2. Description of Related Art
German Offenlegungsschrift 35 32 777 discloses a burner where there is a sleeve-shaped baffle within the flame zone which directs the hot gases in a funnel-shaped motion to a slotted baffle. The baffle slots act as a flame disperser and facilitate an acoustic uncoupling of the burner from other units, like a boiler room or furnace, which results in a muffling of the noise of the burner. The baffle arranged in the flame zone of the burner can also serve as a catalytic agent to reduce pollutants, if required. To this end, the side of the baffle facing the combustion area can be coated with a layer of the catalytic material.
German Offenlegungsschrift 34 13 968 and German Gebrauchsmuster 84 10 034 refer to baffle plates arranged in the combustion chamber, particularly in the area of the flame zone, which carry an exhaust gas catalyst for the removal of pollutants from the combustion gases, particularly NOx.
German Offenlegungsschrift 34 25 259 describes a heat generator with overpressure combustion on an oil or gas basis, having a combustion chamber and a deflection chamber. For the purpose of purification of the exhaust gases, a catalyst is arranged in the deflection chamber, as a coating at the wall of the deflection chamber and/or at the outer surface of an inner cylinder in the combustion chamber.
In conventional heating devices, particularly automotive heating devices, an exhaust gas muffler for silencing the combustion noises is provided and is installed in an exhaust gas line externally of the heating device. Exhaust gas mufflers of this kind represent a separate component which has to be separately manufactured and installed. More specifically, such a muffler is exposed to corrosion from both the outside and the inside. Furthermore, in the startup phase of the heating device, problems may arise which are caused by wet exhaust gases occurring due to the existence of temperatures below the condensation point during the partial load phase as well as during periods with low outside temperatures. This, in turn, can lead to formation of ice and may cause increased resistance in the area of the externally arranged waste gas muffler, leading to a deterioration of the combustion process, and a breakdown of the heating device in extreme cases.